One type of liquid spraying is known as nano-electrospray or nanospray when used as a sample introduction method in mass spectrometry. The sources of generating such a spray may be quartz or glass capillaries tapered to a tip having a predetermined diameter, or they can be microfabricated nozzles made of silicon or other semiconductor or glass, etc. A liquid spraying apparatus can include the spray nozzle and a mechanism for pumping liquid through the nozzle, as well as a high voltage power supply for supplying the electric field for generating the spray.